1. Purification of the cytoplasmic granules of basophils, using preparations of purified guinea pig blood in bone marrow basophils as starting material. Preliminary studies in progress are most encouraging in that we have already been able to obtain granule fractions about 90% pure. 2. Chemical characterization of purified basophil granules with particular regard to the nature of the acid mucopolysaccharide and the nature of the proteins which comprise these granules. 3. Continuation of chemotaxis experiments with purified guinea pig basophils in order to determine whether the lymphokines chemotactic for basophils are manufactured by T or B lymphocytes. 4. Studies of histamine synthesis by guinea pig basophils in tissue culture with emphasis on the effects of histamine liberators and lymphokines on both histamine synthesis and release. 5. Role of basophils in the rejection of guinea pig hepatomas. BIBLIOGRAPHIC REFERENCES: Dvorak, H.F., and Hammond, M.E.: Cutaneous Basophil Hypersensitivity in "Modern Concepts and Developments in Immediate Hypersensitivity", M.K. Bach, editor, Marcel Dekker, Inc., N.Y., in press, 1976. Dvorak, H.F., Mihm, M.C., Jr., and Dvorak, A.M.: Morphology of delayed-type hypersensitivity reactions in man. Brook Lodge Symposium, editors, K.F. Austen and S. Cohen, in press, 1976.